Scraping out device for mining boreholes



June 3, 1952 J. DloNlsoT-n SCRAPING OUT DEVICE FOR MINING BOREHOLES Filed Feb. 21, 1947 Patented June 3, 1952 SCRAPING OT DEVICE FOR MINING BOREHOLES l Joseph Dionisotti, Monthey, Switzerland vApplication February 21, 1947, Serial No. 730,152

In Switzerland February 23, 1946 l Y The chamber destined for the explosive charge at the bottom of a mining borehole is usually made by having therein explode a small charge. The pocket thus obtained is then filled with explosive whose deagration blows up the rock. The rstmentioned explosion, however, causes cracks through which the explosion gases of the main charge escape thereby diminishing the eiliciency. I

In order to remedy these inconveniences and to obtain at the bottom of the mining borehole a chamber with intact walls of precise dimensions corresponding exactly to the necessary charge of explosives, it is recommendable to make this chamber by means of a special scraping out device.

The present invention, therefore, aims at a scraping out device for mining boreholes, characterised by an oscillating boretool, whose cutting part is pro-vided so as to transform the pressure of the drill at least partly intoa radial force, displacing this cutting part from the axis of the borehole for working upon the wall of the latter.

The accompanying drawings illustrate, by Way of example, different embodiments of the scraping out device according to the invention.

Fig. 1 is an axial elevational section of the rst example, of which Fig. 2 is an analogous section but turned by 90 with regard to the former;

Fig. 3 is Van elevation of the same device, Vwith the diii'erent parts in the relative position shown in Fig. 2, however, turned by 90 with regard to the latter.

Fig. 4 is a bottom View of the device according to Fig. 2;

Fig. 5 is an axial section of the second embodiment, of which Fig. 6 is an elevation turned by 90 with regard to the preceding figure.

Fig. 7 is a bottom view of the second example.

Fig. 8 is an elevation View of a third Vembodiment, and

Fig. 9 is a bottom view thereof.

Fig. 10 is a longitudinal, part-sectional View of a modication of a device according to the invention in which a tool as shown in Figures 5 to 9 is supported by the means illustrated in Figures 1 to 4.

Referring now to Figs. 1 to 4, l designates a socket made of two symmetrical plates 20 and 2| contacting each other and held together by a coupling nut 2 whose inside thread is screwed to s Claims. 1(01. c55-76') I a bolt 4 made of the two semi-cylindrical ends of the plates 2li and 2l of the socket l.

On these plates an oscillating tool 5 is mounted, having a semi-elliptical shape and pivoting by hubs 6 made in one piece with the tool, in recesses 1 provided on the plates 20, 2 LL The outer part of the tool comprises a cutting edge 8 and two shorter cutting edges 9 provided laterally to the middle one 8.

The free end of the socket likewise comprises cutting edges H which, when the tool is in the position shown in Figs. 2 and 3 prolong the borehole and guide .in this Way Athe cutting edges 8 and 9 during theirwork.

The hubs 6 instead of lying in the axis of the socket, might be laterally displaced, as indicated in chain-dotted lines in Fig. 2.

Instead of consisting of two pieces, the socket might be made in one piece and the oscillating tool held thereon by means of a separate axle.

The illustrated scraping out device Works as follows: A f Y After having b ored a hole of a certain length into the rock, the scraping out device is inserted into the borehole with the oscillating tool in the position shown in chain-dotted lines in Fig. 2. The cutting edges 9 arriving at the bottom of the bore-,hole and contacting this bottom only by their points, the pressure of the rock drill upon` thesocket is partially transformed into a radial force which tends to displace the oscillating tool from the axis of the-boreholealready.made in order to work upon the wall of the borehole and to enlarge the diameter thereof. The tool having attained the position shown in Figs. 2 and 3 in full lines, the initial borehole at the same time as the scraping out takes place, is continued in its longitudinal direction by the cutting edges I l boring a hole which serves as a guide for the subsequent work.

If the pivot of the oscillating tool is displaced relatively to the longitudinal axis of the socket, the action caused by the percussion and rotation effect of the rock drill, is accentuated.

The device illustrated cannot only be used for scraping out, i. e. for making a hole of greater diameter at the end of a mining borehole already made, but also for commencing and continuing from the front of the rock a borehole having a radius equal to the distance separating the points of the cutting edges from the pivoting center of the tipping tool, after having begun the work by a borehole of the smaller diameter of the socket.

In the embodiment shown in Figs. 5, 6 and 7,

the metallic oscillating tool I2 is crescentshaped. It oscillates around a pivot I3 in a slot I4 of a socket I5 made in one piece. The tool I2 is pierced by a hole I6 which diminishes the weight of the oneV half of the tool I2 so that it returns automatically into the interior of the socket as shown in chain-dotted lines in Fig. 5. A stop pin 31 traversing the slot I4 is provided destined to cooperate with a cut-out 38 of the tool I2 for stopping the latter in its vertical position.

The free end of the socket is likewise provided with cutting edges Il continuing the initial borehole to be enlarged by the tipping tool, this continued part of the borehole serving as a guideduring the scraping out Work.

The efciency of the scraping out device according to the invention can be further increased by providing several crescent-shaped oscillating tools arranged parallel with regard to one another in the interiory of the socket on which they are pivoted. Such a device is shown in Figs. 8 and 9. In a socket 39, made in one piece. two slots 3l are provided inwhich oscillating crescentshaped tools 32 are pivoted on a separate axle 33. They are parallelly disposed with regard to each other and are separated by a fixed Wall 36. Stop pins 31 traversing the slots 3l are provided for stopping tools 32 in their vertical position.

The free end of the socket is provided with cutting edges 35 which work likewise upon the rock. when the tipping tools 32. are in action- By these edges 35 a guide hole is obtained allowing to give the scraping out a determined direction.

The tools I2. or 32 shown in Figures 5 to 9 may be supported b-y means equivalent to those shown in Figures 1 to 4. This modication of the invention is illustrated niFg. 120.

What I claim is:

1. An expansion. drill comprising a.. coupling nut havingy a. bore extending over a portion of its length, an inner, substantially cylindrical por'- tion of the bore being threaded and another adjacent, coaxial outer portion; of the bore being conical; two plates contacting with eachv other along a plane. through thel rotation axis of thel drill, the upper portions of said plates forming togethera screw and an adjacent cone engaging said threaded and said conical portions of said coupling nut, respectively, said plates having grooves adjacent to each other so as to provide a slot, and cylindrical recesses the diameters of which diminish with increasing distancev from said contacting plane and the common axis of which is perpendicular to this contacting plane, and a tool disposed in said slot and having substantially the same Width as said plates, hub portions connected With said tool and rotatably inserted in said recesses, said tool having a cutting edge having the configuration of substantially one half of an ellipse for transforming the pressure of the drill upon advance movement of the coupling nut at least partly into a moment force for Ipivoting said tool into Working position.

2. An expansion. drill comprising, in combination, a socket having a slot with lateral walls parallel to the rotation axis of the drill, and a bore extending throughout the width of the socket along an axis perpendicular to said Walls; a pivot inserted into said bore; a tool lodged in said slot and having a bore by which it is rotatably rmounted on said pivot. and having a cutting edge extending over one half of a substantially elliptical curve, so as to transform" the pressure of the drill occurring on advance movement of the socket at least partly into a moment force used in pivoting said. tool into Working position.

3'. In an expansion drill, a socket having a plurality of slots with lateral walls parallel to one another and to the rotation axis of the drill, and a bore extending throughout the Width of the socket along an axis perpendicular to said walls;

a pivot inserted into said bore; a tool placed in each of said slots and having a bore by which it is rotatably mounted onsaid pivot, and having a cutting edge extending over one half of a substantially elliptical curve, so as tol transform the pressure of the drill occurring on advance movement of the socket into a moment Vforce used in pivoting the tool into working position over substantially JOSEPH DIONISOTTI.

REFERENCES CITED The following references are of record in the Ie of this patent:

UNITED STATES PATENTS Number Name Date 230,863' Cowles Aug'. 10, 1880 309,927 Chap-man D'ec. 30, 1884- 639',036 Heald Dec. 12, 1899 931,021 Adams Aug. 17, 1909 1,357,689 Clark Nov. 2, 1920 1,653,900 Gregory Dec. 27, 1927 2,193,721` Gunderson Mar. 12, V1940 

